Quick question about static IP address config

  • Hi all,

    I have Spectrum/Time Warner Internet for my small business network and I recently purchased a static IP address from them. They sent me instructions with one static IP, one default gateway IP, two DNS servers and a subnet mask.

    I have a cable modem from them, but I assumed that I have to make these changes on the pfSense firewall. I have tried to make all the changes, but I get no Internet. I called customer service and they couldn't give me any useful info on how to fix it.

    Does anyone have any experience with getting a static IP? Do they have to do something on the cable modem in order for all this to work? I don't completely understand how this works, so wondering if someone could help.


  • LAYER 8 Global Moderator

    Can pfsense ping the gateway they gave you?

    Did you power cycle the cable modem after you changed the IP on pfsense wan?

    You sure it was a cable modem, and not a gateway.. ie pfsense had public IP on its wan before?

  • Depending on the provider there is what they call passthru mode or bridged mode.

    DHCP needs to be turned off on the modem and so does NAT and firewall.  If a static has been purchased then at that point it should work.  Understand the process on how to reset your modem just in case the process does not work.

  • I'll second that on what kapara said. However, with an exception.

    I have Specturm at my house and also use PFSense with a static.

    To properly configure a firewall behind a modem. You need to do as kapara stated. You need to have ISP disable DHCP and enable pass-through/bride. Doing so should disable the modems firewall as well and pass all traffic down to your firewall. This way you can properly manage the WAN with your firewall directly. If you do not, you can run into double NAT issues. Basically where lets say you disable SIP on your PFSense box but it wont matter because SIP is enabled at the modem etc….

    However, here is the exception.

    When Specturm normally assigns a static IP to their modems. They do it in DHCP/Static mode. This means that it can do both, however minus the bridge mode (so you will have double NAT) but it SHOULD still work. You should be able to obtain an internet connection and data should flow once you configure your PFSense WAN properly for a static. Then you would call in once everything is functional and have DHCP disabled and bridge modem enabled on the modem.

    They do this so your network wont be down in the time it takes to place in a firewall with the static IP.

    So long story short. Issues seems to be with your PFSense box or the modem.

    So I have a few questions for you

    1. Are you sure you entered in the correct settings in your PFSense WAN? Double check all settings
    2. Is this a new PFSense install/box or have you been using it with this modem previously?

    The second question is pretty important. If this is a new PFSense box that means a new MAC that the modem needs to register when it connects to PFSense box. Ensure your static information was entered correctly, plug your PFSense box to the modem and power cycle the modem. This will allow the modem to release the old routers MAC and obtain a new one, which will be your PFSense box's MAC.

    Sometimes when adding a new firewall, modems and firewalls require multiple reboots in order to flush out the routing tables.

    Hope this helps.

Log in to reply